1. Field of the Invention
The invention relates to a swing frame, more particularly to a swing frame having locking devices for hanging stably a swing chair.
2. Description of the Related Art
Referring to FIG. 1, a conventional swing includes a swing frame 1, a cover frame 2, and a swing chair 3 hung on the swing frame 1. The conventional swing frame 1 comprises a pair of opposite leg frame units 11, a top horizontal bar 12 connected between the leg frame units 11, and a pair of vertical connecting sleeves 121. Each leg frame unit 11 has a front leg rod 111 and a rear leg rod 112 connected to an intermediate portion of the front leg rod 111 by means of screws 15 and nuts 16. Each front leg rod 111 has an open top end 113. Each of the connecting sleeves 121 is welded to a corresponding end of the horizontal bar 12, and has a lower section 122 formed with a decreasing diameter. The lower section 122 is inserted into the top end 113 of a corresponding one of the front leg rods 111, and is retained thereon by means of a pair of clamp plates 13 and a plurality of screws 17.
As mentioned above, the conventional swing frame 1 has two connecting sleeves 121 that are welded to the respective opposite ends of the horizontal bar 12 to connect with the respective leg frame units 11 by screws 15 and nuts 16. Due to the forces induced upon swinging the swing chair 3, the connection between the connecting sleeves 121 and the leg frame units 11 is liable to become loosened after using the swing frame 1 for a short period of time. Furthermore, since the front and rear leg rods 111, 112 are simply connected by welding and screw connection, when the swing frame 1 supports a heavy load, the front and rear leg rods 111, 112 are easily disintegrated.
Therefore, the main object of the present invention is to provide a swing frame having stable locking devices in order to overcome the aforementioned drawbacks of the prior art.
Accordingly, a swing frame of this invention comprises a pair of support frame units, a hollow horizontal bar, and two primary locking devices. Each of the support frame units includes an upper portion, a lower portion opposite to the upper portion, and an intermediate portion connecting the upper and lower portions. The upper portion is formed with a horizontal hollow tube at the top end thereof. The hollow horizontal bar is adapted to hang a swing chair, and has opposite end portions that are inserted respectively into the hollow tubes of the support frame units. The primary locking devices are disposed respectively on the end portions of the horizontal bar to lock the end portions of the horizontal bar relative to the hollow tubes.